I had a potential problem that we detected and it's a good thing we did!

I bought a bunch of gear from a field that closed when the owner passed away. The nice folks that sold it to me really didn't know much about it and that's fine. In the package was 4 yellow 4500 PSI cascade tanks. Except one wasn't. In the mix was a 50 pound CO-2 cylinder. It had been painted yellow to match the cascades and the height was the same. But it had different size threads for the travel cap. That was the first warning flag. The valve didn't seem original. So we started researching. Somewhere the valve had been replaced and a HPA on off had been installed. There is a difference in the two and many have ID numbers stamped into them to tell. SO we ended up taking the advice of our CO-2 supplier and put a wire brush to the shoulder of the tank to uncover any marking hidden by the many coats of paint. After a few minutes we found the pressure rating 2050 PSI. It would have been a bad day to push that to 4500. The valve replacement means the blow off disc was for HPA so it would have made the weak link in the system the tank itself!

I'm sure the guy must of had a plan for what he was doing, but this could have been very bad. I'm sending the tank out to re-valve and re-hydro so it can be used again. It will be interesting to see if the tank has been stressed to the point it won't pass a hydro test!

Good catch! High pressure tanks are one of those things I just don't mess around with. I ran across a scuba tank of a certain year and alloy makeup that, if miss handled or misused, had a bad habit of exploding. Instead of sending it in for a specialized test, I just removed the reg, drilled a large hole and scrapped that sucker.